When I took my first look at the cover of “Absence” by Andrew Dana Hudson, several possible topics regarding the one-word title came to mind. Hmm, I thought. I wonder what kind of absence he’s talking about. Maybe it’s about a messed-up kid who always skips school. Maybe it’s about a person who always manages to not be there when scary or difficult situations arise. But I could have taken a hundred guesses, and none would be anywhere near author Hudson’s perspective on or exploration of the subject. The plots, the themes, the narration, and the dialogue all deal with the horror and mystery of how every person on earth would deal with the reality that strikes the people of this novel. That is: Individuals or groups of people suddenly disappear, without warning, without reason, without logic, without explanation. They are here and then they are not. They simply pop away. The event becomes known as popping. Two people are talking or driving together or making love, and suddenly only one is there, the other temporarily replaced by a vacuum, which itself disappears almost immediately. A popping sound is always heard when the victim goes away.